Experimental and numerical investigation on the fatigue behaviour of friction stirred channel plates

The friction stir channelling (FSC)process is a technological innovation based on the friction stir fundamentals. To produce friction stirred channel components, a non-consumable tool, similar to that used for friction stir welding (FSW), is used. Friction stir channelling is a single step manufacturing process in which a continuous channel with a specific path is produced in a monolithic metal component. This work discusses the influence of the channel geometry on the bending strength of friction stirred channel aluminium alloy specimens, as well as their fatigue behaviour. Moreover, fatigue analyses using the finite element method were also carried out, considering the channels' geometrical features in order to assess and compare the fatigue lives. The stress intensity factor for different crack lengths was determined using ABAQUS. The fatigue crack growth curve was established according to the Paris Law, and the crack was only allowed to propagate along the materials interface. It was observed that the critical zones are located in the vicinity of the channel corners and found that the fatigue crack propagation period on FSC specimens is very short compared to the crack initiation period. Base and FSW material properties play a major role on fatigue crack propagation simulation. The accuracy of the predicted results increased when considering lower stress amplitudes and by using the FSW material parameters.